The Crucial Role of Chromogranins in Storage and Exocytosis Revealed Using Chromaffin Cells from Chromogranin A Null Mouse
| Autor: | J. David Machado, O Humberto Viveros, Diego Alvarez de la Rosa, Marcial Camacho, Agustín Castañeyra, Daniel T. O'Connor, Sushil K. Mahata, Emilia Carmona, Jesica Diaz, Mónica S. Montesinos, Yezer G Morales, Ricardo Borges |
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| Rok vydání: | 2008 |
| Předmět: |
endocrine system
Vesicle fusion Tyrosine 3-Monooxygenase Chromaffin Cells Dopamine Agents Biology Membrane Fusion Exocytosis Levodopa Mice Catecholamines Adrenal Glands Chromogranins Electrochemistry Animals Secretion Cells Cultured Probability Mice Knockout General Neuroscience Vesicle Chromogranin A Articles Secretory Vesicle Cell biology Mice Inbred C57BL Biochemistry biology.protein Neurosecretion |
| Zdroj: | The Journal of Neuroscience. 28:3350-3358 |
| ISSN: | 1529-2401 0270-6474 |
| DOI: | 10.1523/jneurosci.5292-07.2008 |
| Popis: | Chromogranins (Cgs) are the major soluble proteins of dense-core secretory vesicles. Chromaffin cells fromChganull mice [chromogranin A knock-out (CgA-KO)] exhibited ∼30% reduction in the content and in the release of catecholamines compared with wild type. This was because of a lower secretion per single exocytotic event, rather than to a lower frequency of exocytotic events. Cell incubation withl-DOPA produced an increase in the vesicular amine content of wild-type, but not CgA-KO vesicles. In contrast, intracellular electrochemistry showed thatl-DOPA produced a significantly larger increase in cytosolic amines in CgA-KO cells than in the wild type. These data indicate that the mechanisms for vesicular accumulation in CgA-KO cells were fully saturated. Patch-amperometry recordings showed a delayed initiation of the amperometric signal after vesicle fusion, whereas no changes were observed in vesicle size or fusion pore kinetics despite the smaller amine content. We conclude that intravesicular proteins are highly efficient systems directly implicated in transmitter accumulation and in the control of neurosecretion. |
| Databáze: | OpenAIRE |
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